Advances in Environmental Biology Orthosiphon Stamineus Relative Humidity Storage Condition

Advances in Environmental Biology, 8(22) November 2014, Pages: 99-102
AENSI Journals
Advances in Environmental Biology
ISSN-1995-0756
EISSN-1998-1066
Journal home page: http://www.aensiweb.com/AEB/
Quality Changes of Orthosiphon Stamineus Dried Herbal Leaves Under Extremely Low
Relative Humidity Storage Condition
1
Norawanis Abdul Razak, 2Abdul Razak Shaari, 1Ibni Hajar Rukunudin and 1Muhammad Syarhabil
Ahmad
1
School of Bioprocess Engineering, Universiti Malaysia Perlis (UniMAP), Kompleks Pusat Pengajian Jejawi 3, 02600 Arau, Perlis,
Malaysia
2
Faculty of Engineering Technology, University Malaysia Perlis (UniMAP), Pauh Putra Main Campus, 02600 Arau, Perlis, Malaysia,
ARTICLE INFO
Article history:
Received 25 September 2014
Received in revised form
26 October 2014
Accepted 25 November 2014
Available online 31 December 2014
Keywords:
Storage condition, natural herbal,
relative humidity
ABSTRACT
The experiment was conducted to determine the effects on the physical appearance and
bioactive compounds content when Orthosiphon stamineus dried herbal leaves were
stored under the extremely low condition at 10% relative humidity for 180 days. The
moisture content changes were examined using a moisture analyzer and the color
changes were analyzed using colorimeter. The total phenolic compounds and
antioxidant activity were measured using the Folin-Ciocalteu method and 2,2-diphenyl1-picrylhydrazyl (DPPH) free radical scavenging activity assay respectively, and
analyzed using UV/VIS Spectrophotometer. The biomarkers were determined using
high performance liquid chromatography (HPLC). The results showed that storing O.
stamineus dried herbal leaves under very low relative humidity had largely affected the
herbal leaves quality. After 180 days of storage time, the color of samples turned to
dark-yellow and the moisture content declined to 7.38% wet basis. Antioxidant capacity
exhibited an increase in value. Meanwhile, total phenolic content did not change during
storage. Rosmarinic acid significantly increased during storage time from 2.89 to 6.58
mg/g. The TMF, sinensetin and eupatorin increased to 48.31, 29.04 and 7.92 ug/g,
respectively, at day 90. On day 180, TMF decreased to 11.01ug/g and sinensetin
maintained at 19.48 ug/g. However, eupatorin was not detected at day 180 of storage
time. The optimum storage condition should be monitored in order to maintain the
quality of raw herbal materials for further processing.
© 2014 AENSI Publisher All rights reserved.
To Cite This Article: Norawanis Abdul Razak, Abdul Razak Shaari, Ibni Hajar Rukunudin and Muhammad Syarhabil Ahmad., Quality
Changes of Orthosiphon Stamineus Dried Herbal Leaves Under Extremely Low Relative Humidity Storage Condition. Adv. Environ. Biol.,
8(22), 99-102, 2014
INTRODUCTION
The usage of herbs in daily practice is rapidly increasing nowadays. Some of them are claimed to be a good
method of treatment for chronic diseases such as kidney problem, diabetes, hypertension and cancer [1]–[4].
Usually, these processed herbal plants are produced in tablets, capsules, sachets, concentrated liquid and so on.
The quality of the final products should be prioritised before they are distributed to the consumers. Generally,
the quality of herbal products disappears during the production processes especially when heat is involved [5].
Production chain of herbal products commonly included drying, storage of herbal raw materials, extraction,
granulation, compression, packaging, final product storage, transportation and marketing. Each process may
affect the consistency and quality of herbal products. Thus, the optimum quality should be monitored at each
level of the production process. A lot of studies had been done on the processes mentioned earlier but researches
on storage are limited. The entrepreneurs have a correct indication to control the quality of the final products.
However, the effect of storage towards the plant‟s quality is not fully explored yet by the researchers, especially
for local herbs. Therefore, this study was conducted to investigate the effect of extremely low relative humidity
storage condition on the physical appearance and chemical quality of O. stamineus dried herbal leaves. This
condition was selected based on one of our country‟s climate, the drought season. During this season, the
storage room temperature may increase and becomes extremely dry. Not all entrepreneurs can afford to use air
conditioner in their storage room. This study was performed on selected potential herbs, O. stamineus or locally
known as „misai kucing‟, which is believed to be able to treat chronic diseases such as diabetes and cancer [6].
Corresponding Author: Norawanis Abdul Razak, 1School of Bioprocess Engineering, Universiti Malaysia Perlis
(UniMAP), Kompleks Pusat Pengajian Jejawi 3, 02600 Arau, Perlis, Malaysia
E-mail: [email protected]
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Advances in Environmental Biology, 8(22) November 2014, Pages: 99-102
Additionally, this herb is also believed to be capable of curing gout, kidney stones, high blood pressure, fever,
and more [7]. In this study, the main factors were extremely low relative humidity storage condition at 10%RH
and storage time. This study was expected to be a useful reference especially for entrepreneurs who are
currently active and interested in natural herbal food industry.
METHODS AND MATERIALS
Raw Material Preparation. O. stamineus plants were obtained from Sustainable Agrotechnology Institute,
Universiti Malaysia Perlis (UniMAP) crop field. The cleaned plants were air dried at ambient temperature for 7
days. Only part of leaves was utilized in this experiment to control the consistency of further analysis.
Storage Treatment. The extremely low relative humidity (±10%RH) storage condition was set up in
desiccator using saturated salt, lithium chloride as described by Greenspan [8]. The consistency of relative
humidity was monitored using a digital hygrometer which was located in each desiccator. 10 g of O. stamineus
dried herbal leaves were stored for treatment in each desiccator. Three different rooms with the temperature of
±25°C were utilized as a treatment replication. The readings were taken at the 0, 90 and 180 day of storage time.
Each sample was considered as independent samples.
Sample Preparation. 1 g of O. stamineus dried herbal leaves was extracted by 100ml of distilled water for 3
hours at 40°C using a shaker water bath (Thermolab, Germany).The extracted solution was filtered using
Whatman No.1 filter paper and then were sealed in the bottles and stored in a freezer (-20°C) for chemical
quality analysis.
Determination of Color. An average of six readings was taken from individual sample of O. stamineus dried
herbal leaves using colorimeter CR-400 (Konica Minolta, Japan). The collected data were available in the form
of L*, a* and b* color space (CIELAB).
Determination of Moisture Content. The MS-70 moisture analyzer (A&D, Japan) was used to read the 1g
sample‟s moisture.
Determination of Total Phenolic Content. 200µl of Follin-Ciocalteu reagent (FCR) and 200µl of extract
solution were mixed with 1.58 ml distilled water and shook rigorously for 4 minutes before adding 1 ml of 20%
sodium carbonate. The mixed solution was allowed to react for 2 hours in a dark place. The concentration of
total phenolic content was quantified using UV/VIS spectrophotometer (Shimadzu. Japan) and the absorbance
was read at λ=760nm. The caffeic acid was used as standard and the concentration of total phenolic content was
expressed in caffeic acid equivalent (CAE).
Determination of Antioxidant Capacity. The antioxidant capacity of the extracts was determined using the
modified DPPH method as described by Akowuah [9]. About 2 ml of 2,2-diphenyl-1-picrylhydrazyl (DPPH)
was mixed with 200 µl aliquots of samples. Methanol was used to mark up the mixture to 3 ml. The mixed
solution was allowed to react in a room temperature for 1 hour. The control was also prepared. After 1 hour, the
absorbance value was calculated using a UV/VIS spectrophotometer (Shimadzu, Japan) at λ=517nm. The
antioxidant capacity of samples was estimated by utilizing the following equation:
𝐴−𝐵
Antioxidant capacity =
× 100 ; Where A = Control absorbance, B = Sample absorbance
(1)
𝐴
HPLC Analysis. High performance liquid chromatography, HPLC (Shimadzu, Japan), used was equipped
with degasser, an auto sampler, a column heater, quaternary pump and UV detector. The column (A LiChrosorb
RP-18, 250mm x 4.6mm, 5µm) was maintained at 30°C and the injected sample, about 20µl, was eluted with
isocratic mobile phase comprising of methanol: tetrahydrofuran: acidic water (pH3) mixture in the volume ratio
45:5:50. The flow rate was 1 ml/min, 40 min separation time and detection at 340nm. Standard calibration
curves were made by plotting the peak area against concentration. The quality reference compounds used were
rosmarinic acid (Sigma-Aldrich, U.S.A), 3‟-hydroxy-5,6,7,4‟-tetramethoxyflavone, TMF (Indofine, U.S.A),
sinensetin (Indofine, U.S.A) and eupatorin (Indofine, U.S.A).
Statistical Analysis. All measurements were carried out in triplicate and the results are statistically analyzed
using JMP pro 11 package to determine the average value and standard error.
RESULTS AND DISCUSSIONS
Effect of Extremely Low Relative Storage Condition on Appearance Quality:
Moisture Content Changes:
The changes of moisture content on O. stamineus dried herbal leaves were plotted against storage time in
days under extremely low relative humidity as shown in Fig. 1. The results obtained from the ANOVA analysis
showed that there was a significant change of moisture content by storage time (pvalue=0.0007). The initial
moisture content at 0 days starting from 10% (wet basis) significantly declined at day 90 (pvalue =0.0008). This
phenomenon could be labeled as desorption process where the environment absorbed the molecules of water
from the samples [10]. After 90 days of storage time, the changes of moisture content seem to be maintained
(pvalue =0.1756). At this stage, equilibrium moisture content was achieved[11].
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Fig. 1: The changes of moisture content of samples during 180 days of storage time under extremely low
relative humidity storage condition. Means (n=3) with different letter are significantly different at 95 %
confidence level.
Colour Parameters:
The changes of color parameters by storage time are represented in Table 1. The positive value of L* and
b* were referred to lightness and yellowness. The negative value of a* was refered to greenness of sample‟s
colour [12]. The results obtained from ANOVA analysis showed that there were significant changes of L*, a*
and b* by storage time (pvalue=0.0101, pvalue=0.0007 and pvalue=0.0088, respectively). The L* value significantly
maintained around 47.18 to 48.11 between the initial and day 90 of storage time (pvalue=0.2578). However at
day 180, the L* value reading significantly decreased to 44.73 (pvalue=0.0040). The a* value significantly
decreased to -0.63 at day 90 of storage time (pvalue=0.0019) and maintained around -0.39 at day 180 of storage
time (pvalue=0.0537). The b* value significantly increased from 5.40 to 7.19 at day 90 of storage time
(pvalue=0.0089) and then the b* value maintained at day 180 of storage time around 7.49 (pvalue=0.5431).
Table 1: The changes of colour parameters on samples of O. stamineus dried herbal leaves during the 180 days of storage time under
extremely low relative humidity storage condition.
Storage time (Days)
L*
a*
b*
0
47.18a
-1.16b
5.40b
90
48.11a
-0.63a
7.19a
180
44.73b
-0.39a
7.49a
*Means (n=3) with different letters in a single column are significantly different at the 95 % confidence level.
Effect of Extremely Low Relative Storage Condition on Chemical Quality:
Antioxidant and Total Phenolic Content:
Fig. 2 shows the changes of antioxidant capacity (%) and total phenolic content on samples of O. stamineus
dried herbal leaves stored for 180 days under extremely low relative humidity storage condition. From the
ANOVA analysis result, antioxidant capacity significantly increased by storage time (pvalue <0.0001).The
antioxidant capacity significantly increased from 72.79 to 79.30% at day 90 of storage time (pvalue =0.0007) and
slightly increased to 82.45% at day 180 of storage time (pvalue =0.0030). This finding was similar to previous
research done by Toor and Savage [13]. They claimed that antioxidant capacity of tomatoes increased during
storage. Leja and friends also claimed that antioxidant capacity of broccoli flower bud increased during storage
[14]. However, the quantity of total phenolic content in the samples significantly was not affected by extremely
low relative humidity storage condition and storage time (pvalue =0.5729).
Fig. 2: The changes of antioxidant (left) and total phenolic content (right) on samples of O. stamineus dried
herbal leaves during the 180 days storage time under extremely low relative humidity storage condition.
Means (n=3) with different letter are significantly different at 95 % confidence level.
Biomarker Compounds Content:
Table 2 shows the changes of biomarker compounds on samples of O. stamineus dried herbal leaves during
the 180 days storage time under extremely low relative humidity storage condition. In this study, four important
biomarker compounds of O. stamineus were selected; rosmarinic acid, 3‟-hydroxy-5,6,7,4‟-tetramethoxyflavone
(TMF), sinensetin and eupatorin. The results obtained from the ANOVA analysis showed that there were a
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significant change on rosmarinic acid (pvalue=0.0065), TMF (pvalue=0.0030), sinensetin (pvalue=0.0031) and
eupatorin (pvalue=0.0061). The mean value of rosmarinic acid significantly increased during 180 days of storage
time from 2.89 to 6.58 mg/g (pvalue=0.0058). The mean value of TMF, sinensetin and eupatorin increased to
48.31 (pvalue=0.0015), 29.04 (pvalue=0.0011) and 7.92 ug/g (pvalue=0.0155), respectively, at the 90 day of storage
time and significantly maintained at 19.48 ug/g until day 180 for sinensetin (pvalue=0.0801) but significantly
dropped to 11.01ug/g for TMF (pvalue=0.0083). The eupatorin decreased (pvalue=0.0022) and was considered as
not detected at day 180 of storage time.
Table 2: The changes of biomarker compounds on samples of O. stamineus dried herbal leaves during the 180 days of storage time under
extremely low relative humidity storage condition.
TMF
Sinensetin
Storage time (Days)
Rosmarinic acid (mg/g)
Eupatorin (ug/g)
(ug/g)
(ug/g)
0
2.89b
4.62b
2.51b
2.72b
90
2.58b
48.31a
29.04a
7.92a
180
6.58a
11.01b
19.48a
0.00b
*Means (n=3) with different letter in a single column are significantly different at 95 % confidence level.
Conclusion:
As a conclusion, the data collected in this paper showed that extremely low relative humidity significantly
affected the quality of O. stamineus dried herbal leaves during 180 days of storage time. The samples became
drier and crunchy. The sample's color changed to dark-yellow. Antioxidant increased by storage time. Total
phenolic content maintained along the storage time. The chemical quality of the sample increased when the
moisture content decreased under extremely low relative humidity storage condition for O. stamineus dried
herbal leaves. These finding might be used as an indicator for similar local dried herbal leaves to control the
quality of raw herbal material in producing a great quality of herbal finished products.
ACKNOWLEDGEMENT
This work was sponsored by the Ministry of Higher Education Malaysia (Grant code: FRGS 9003-00353).
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